The term ERNE OR TERN is a 7-letter sea bird. The Erne or Tern is a type of SEABIRD that is found in many parts of the world, including Europe, Asia, and North America. It is a medium-sized bird with a long, pointed bill and long, forked tail. It feeds mainly on fish, but also eats insects, crustaceans, and other small animals. It nests in colonies on the ground or in trees, and its eggs are laid in shallow depressions.